Critical temperature T(c) and memory kernel in molecular-dynamics-simulated glass-forming Ni(0.2)Zr(0.8)

The mode-coupling theory (MCT) of dense liquids marks the dynamical glass transition by a critical temperature T(c) that is reflected in the temperature dependence of a number of physical quantities. Here, molecular-dynamics simulation data of a model adapted to Ni0.2Zr0.8 are analyzed to deduce T(c) from different quantities and to check the consistency of the estimated values. Analyzed are the critical temperature T(c) from (i). the nonvanishing nonergodicity parameters as asymptotic solutions of the MCT equations in the arrested state, (ii). the g(m) parameters describing the approach of the melt towards the arrested state on the ergodic side, (iii). the diffusion coefficients in the melt, and (iv). the alpha-relaxation time. The resulting T(c) values are found to agree within about 10%. In addition, the time dependent memory kernel is calculated from the MCT for the incoherent intermediate scattering function around T(c) and compared with the kernel obtained by inverting the molecular dynamics data for the corresponding correlator.